Effect of La2O3 and CeO2 loadings on formation of nickel-phyllosilicate precursor during preparation of Ni/SBA-15 for hydrogen-rich gas production from ethanol steam reforming

Abstract

The importance of La2O3 or both La2O3 and CeO2 promoters on the formation of nickel phyllosilicate (Ni3Si4O12H2) as a precursor of Ni/SBA-15 for ethanol steam reforming (ESR) was investigated. The catalyst was made by a one-step modified conventional triblock copolymer synthesis method (pH-Adjustment with ammonium hydroxide). The prepared catalysts were characterized by N2 adsorption/desorption isotherms, XRD, H2-TPR, SEM-EDS and TGA-DSC techniques. The N2 adsorption/desorption isotherms identified the mesoporous nature of the catalysts and the XRD patterns of the calcined catalysts confirmed the formation of nickel-phyllosilicate structure. The H2-TPR analysis revealed that the La2O3 loading considerably increased the interaction between nickel and silica frame work of SBA-15 support. The ability of these catalysts for hydrogen production from ethanol steam reforming (ESR) was evaluated in a packed bed reactor at 650 °C. In the case of Ni/SBA-15 catalysts without and with La2O3 promoter, the ESR experiments experienced metal sintering and coke formation. Meanwhile, the catalytic activity of both La2O3 and CeO2 promoted Ni/SBA-15 catalyst (Ni-La2O3-CeO2/SBA-15) remained stable with time on stream in terms of GPR and hydrogen selectivity. The stable performance of this catalyst was explained by the strong interaction of nickel with SBA-15 promoted by La2O3 and the suppression of coke formation by CeO2.